<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

    <script src="https://unpkg.com/vue@next"></script>

</head>
<body>

<div id="app">
    性别:<br/>
    男、<input type="radio" value="man" name="sex" v-model="mySex"><br/>
    女、<input type="radio" value="woman" name="sex" v-model="mySex"><br/>
    {{mySex}}
</div>

</body>

<script>
    Vue.createApp({
        data() {
            return {
                mySex:'woman'
            }
        }
    }).mount("#app")
</script>

</html>